"Hong Kong physicists say they have proved that a single photon obeys Einstein's theory that nothing can travel faster than the speed of light -- demonstrating that outside science fiction, time travel is impossible."http://news.yahoo.com/hong-kong-scienti ... 26913.html

Now, if time travel is impossible, would that not pretty much put an end to the discussion of how UFOs could possibly get here since that's usually the leading explanation?

Well, although scientifically speaking nothing is impossible, the point they are trying to make is that time travel was previously thought to be highly improbably, but now they figure it's just as close to impossible as possible... (Hell, I don't know, I didn't write the darn paper...)

Well, although scientifically speaking nothing is impossible, the point they are trying to make is that time travel was previously thought to be highly improbably, but now they figure it's just as close to impossible as possible... (Hell, I don't know, I didn't write the darn paper...)

Well, although scientifically speaking nothing is impossible, the point they are trying to make is that time travel was previously thought to be highly improbably, but now they figure it's just as close to impossible as possible... (Hell, I don't know, I didn't write the darn paper...)

Here's a question: I'll say it's impossible for me to take a flying leap and land in Australia. Now, is that impossible or highly improbable? Technically, it would be highly improbable, but at what point, statistically speaking, does an action become so highly improbable that it should be considered impossible for all intents and purposes?

ProfWag wrote:Here's a question: I'll say it's impossible for me to take a flying leap and land in Australia. Now, is that impossible or highly improbable? Technically, it would be highly improbable, but at what point, statistically speaking, does an action become so highly improbable that it should be considered impossible for all intents and purposes?

It is possible that next time I go to open a door that my hand will pass through it. But it is highly improbable. Extremely highly improbable. So why call it impossible?

Now, I could go with the qualifier "as far as we know", I guess. So its impossible, as far as we know, for anything to travel faster than the speed of light. Or: "we know of no way for an object - even a phton - to travel faster than the speed of light. But why go to impossible? It just sounds dogmatic and frankly doesn't add any understanding.

We have no idea what may be discovered in the future. Perhaps there is technology that allows one to bend space time and travel through unscathed. Or travel through a worm hole. Or pass through universes, or any number of imagined or unimagined things. Perhaps if humanity survives for a million more years much of what we think is impossible will have become possible.

Again: we don't need to go there, and you will simply get negative reactions and accusations of dogmatism.

ProfWag wrote:Here's a question: I'll say it's impossible for me to take a flying leap and land in Australia. Now, is that impossible or highly improbable? Technically, it would be highly improbable, but at what point, statistically speaking, does an action become so highly improbable that it should be considered impossible for all intents and purposes?

The big problem with saying that its impossible is that we don't know what we might learn in the future that would change our assessment of the situation. I agree that based on what we currently know, it may be impossible. You've heard me argue the distance problem is one of the biggest reasons to doubt aliens have visied this planet. But we don't know what physics may be discovered in the future that changes the whole picture. Maybe a hypedrive is possible. Or bending space time. Or something else. We just don't know.

We're just plain better off staying away from impossible: what is the benefit in using that term?

Arouet wrote:We're just plain better off staying away from impossible: what is the benefit in using that term?

But it's impossible to stay away from that word on this forum! Just like it's impossible to stay away from a classic YouTube video as solid proof:

It's impossible to tell the sun to leave the sky,It's just impossible.It's impossible to ask a baby not to cry,It's just impossible.Can I hold you closer to meAnd not feel you going through me,But the second that I never think of you?Oh, how impossible.